Thinly slice the flank or skirt steak against the grain and place it in a bowl. Add soy sauce, peanut oil, and cornstarch, mixing well to coat the beef evenly. Let it marinate for 10-15 minutes.

In a separate bowl, whisk together chicken stock, Shaoxing wine, soy sauce, brown sugar, and cornstarch until fully combined. Set it aside.

Heat a large pan over medium heat, adding just a splash of water. Add the broccoli florets and cover the pan. Steam for about 1 minute.

In the same pan, heat 2 tablespoons of peanut oil over high heat. Add the marinated beef in a single layer and sear for 30 seconds. Flip and sauté for an additional 1-2 minutes until browned.

Add minced garlic and ginger to the pan and cook for about 30 seconds until fragrant.

Return the sautéed broccoli to the pan, pour in the prepared sauce, and stir together. Cook for about 1 minute until sauce thickens.

Remove from heat and transfer to a serving dish. Garnish with toasted sesame seeds and serve immediately over jasmine rice or noodles.